Cryptographic machine



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Nov. 13, 1945. TAN-N CRYPTOGRAPHIC MACHINE Filed May.5, 1945 6 Sheets-Sheet 6 122 @5M,WM @gM-M, v W5 Patented Nov. 13, 1945 UNITED STATES PATENT OFFICE CRYPTOGRAPHIC MACHINE Beue Tann, Washington, D. 0. Application May 5, 1943, Serial No. 485,781

23 Claims.

ing it practically impossible to decode the message or the like without the use of a similar machine and without a prior knowledge of the code setting of the machine.

It is an object of my invention to provide a cryptographic machine including a fixed set of letters, characters, figures, words, signs or symbols which may constitute the elements of the clear text, and a movable set or sets of letters, characters, figures, words, signs or symbols which may constitute the elements of the code or cipher text, and to provide a novel and efiicient means for successively and progressively moving one set or sets of the text elements with respect to the other set or sets in a great number of diiierent combinations or relationships to thus avoid repetition of the coded and decoded message or of parts thereof, to effectively maintain the secrecy of successive messages.

It is an object of my present invention to provide a cryptographic machine in which a fixed set of letters or other indicia has associated therewith a movable set or sets of letters or other indicia and in which the positions or relationships between the movable set or sets may be successively and progressively varied with respect to the fixed set, by determining the extent of movement imparted to the movable set or sets by an operating member which controls and efiects the operation of the movable set or sets with respect to the fixed set of letters or other indicia.

It is an object of my invention to provide a cryptographic machine in which a set of letters or other indicia is fixed with respect to the casing of the machine and has associated therewith a movable set of letters or other indicia which with said fixed set may constitute the elements of the clear text, and to associate with the elementsoi the clear text a set or sets of letters or other indicia which are movable with respect to the elements of the clear text and which may constitute the elements of the code or cipher text,

and to provide a, novel and efficient means for successively and progressively varying the extent of movement of the movable set or sets with respect to the fixed set whereby an exceedingly great number of relationships may be obtained or cover member between the fixed and movable sets of the elements of the clear and code or cipher text.

7 It is an object of my invention to provide a cryptographic machine of the character above mentioned in which the movement of the movable set or sets of letters or other indicia is effected by suitable, pawl-and-ratchet mechanism actuated by an oscillating member which, in turn, is under the control of the operator of the machine, and to provide a novel means by which the extent of movement of the oscillating member is successively and progressively varied to vary the extent of movement imparted by the pawland-ratchet mechanism to the movable set or sets of letters or other indicia.

It is a still further object of my invention to provide a cryptographic machine of the character above mentioned in which the movement of the oscillating member, and hence, the movement of the movable set or sets of letters or other indicia, is determined by the position of a rotary member having variously-spaced stop surfaces or shoulders thereon adapted to be engaged by the oscillating member during the operation of the machine, the position of these stop surfaces or shoulders being successively and progressively varied during the coding and decoding operations to thus vary the extent of movement imparted to the movable set or sets of letters or otherindicia.

It is a still further object of my invention to provide a cryptographic machine of the character above mentioned in which the various component parts of the machine may be assembled and associated in an almost infinite number of relative positions to thereby vary, to a very great extent, the relationshi existing between thesets of fixed and movable letters or other indicia.

In the accompanying drawings forming a part of my present application, and wherein, for the purpose of illustration, I have shown several preferred embodiments of my invention,

Figure 1 is a plan view of the cryptographic machine of my present invention,

Figs. 2, 3, 4, 5 and 6 are plan views of separate disc-like members adapted for assembly on a common shaft and which, when assembled, constitute an important element of my present invention,

Fig. 'l is a plan view of the assembled disc-like members shown in Figs. 2 to 6 inclusive,

Fig. 8 is a vertical sectional view on the line 8-8 of Fig. 1,

Fig. 9 is afragmentary plan view of the cryptographic machine shown in Fig. l, with the top of the machine removed and certain portions broken away in order to show the underlying mechanism,

Fig. is a vertical sectional view on the line ill-Ill of Fig. 9,

Fig. 11 is a plan view of a modified form of my invention,

Fig. 12 is a Vertical sectional View on the line lZ-IZ of Fig. 11,

Figs. 13 and 14 are plan views of separate disclike members adapted for assembly on a common shaft and which, when assembled, constitute an important element of that form of my invention shown in Figs. 11 and 12,

Fig. 15 is a fragmentary plan view of a further modified form of my present invention,

Fig. 16 is a side elevation of that form of my invention shown in Fig. 15, and

Figs. l7, 18, 19, 20 and 21 are plan views of separate disc-like members adapted for assembly on a common shaft and which, when assembled, constitute an important element of that form of my invention shown in Figs. 15 and 16.

Referring to the drawings wherein like reference numerals have been used to designate like parts throughout the several views, the numeral I designates broadly the casing or housing of the machine, which casing or housing includes a base 2, upstanding side walls 3 and 4, a curved end wall 5, a platform ii, and a cover or top The particular shape and construction of the casing or housing I is relatively unimportant and forms no part of my present invention. The cover or top I is provided with a semi-circular cut-out portion or window 8, and projecting inwardly from the curved wall defining said semi-circular cut-out portion are a plurality of substantially rectangular, relatively thin, spaced tabs ii, preferably thirteen in number, and each inscribed with a letter of the alphabet. These tabs 9, as shown in Fig. l, are inscribed with the letters B, D, F, H, J, L, N, P, R, T, V, X and Z, 1'. e., with progressively alternate letters of the alphabet beginning with B and ending with Z.

A vertical shaft is journalled for rotation in a bearing ll secured to the base 2 and has its upper end extending through an aperture in the platform ii, which upper end terminates in the plane of the cover or top "l at a point approximately at the center of the semi-circular cut-- out portion or window eyed or otherwise secured to the shaft ill for rotation therewith a ratchet wheel the upper surface of which, as viewed in Figs. 8 and 10, is disposed in parallel spaced relation below the under surface of the platform 6. A lever arm lI-l is positioned between the ratchet wheel l2 and the underside of the platform 6 and has its inner end mounted for pivotal movement about the shaft it its outer end provided with an upstanding lug or abutment I l adapted to extend through, and to terminate above, an arcuate slot Hi out through theplatform Intermediate the ends of the lever arm #3 and pivotally mounted on the underside thereof is a pawl 66, to the outer or free end of which is attached a tension spring ll which tends to maintain the pawl in contact with the teeth on the periphery of the ratchet wheel 12 but which permits the lever arm It to move in a clockwise direction as viewed in Fig. 9, without affecting the position of the ratchet wheel it. A spring-actuated pivoted pawl i8 is mounted on the underside of the platform 6, this pawl permitting counterclockwise rotation of the ratchet wheel. l2 but preventing clockwise rotation there of. When the lever arm ill is oscillated about aaeaoes the shaft iii by mechanism to be hereinafter described, the pawl i6 mounted on the said lever arm wil cause the ratchet wheel 12 and shaft it to rotate in counter-cloclmvise direction when the said lever arm is moved in a counter-clockwise direction, during which movement the pawl iii in no way interferes with the rotation of the ratchet wheel iii. A tension spring l9 extends between the lever ar .1 l3 and a fixed point on the underside of the platform ii, this spring serving to maintain said arm against a fixed stop 2b] which depends from the underside of the platform A second fixed stop 2i also depends from the underside of the said platform, the distance between the stops Sill and 21 being such that for each COLllllLGT-C1OCkWiS movement of the lever arm it, said arm moves only for a suflicient distance to cause the ratchet wheel I2 to move a distance equivalent to the spacing between adjacent teeth on the periphery of said ratchet wheel. Immediately above the platform 6 is a disc if; having aradial arm 23 and a second radial arm 24, this disc being pivctally mounted on the shaft ill. The arm 23 overlies the arcuate slot l5 and during its oscillation in a counterclockwise direction as viewed in Fig. 9, is adapted to c011- tact the abutment M on the lever arm 4 3 to effect a step-by-step rotation of the ratchet wheel It. The outer or free end portion of the arm 24 is bent downwardly to provide a depending portion 25, the purpose of which will be hereinafter described. A pawl is pivotally mounted on arm 23 and is resiliently urged in a counter-clockwise direction by a tension spring 2"! which extends between said pawl and a fixed point on the disc 22. A pair of spaced, spring pressed pawls 28 and 29 are mounted on the upper surface of the platform 6, the springs associated with said pawls tending to urge them in a counter-clcclrwise clirection about their pivotal mountings,

Immediately above the disc 22 is a ratchet wheel all provided with a circular series of holes M, This ratchet wheel is preferably provided with a total of fifty-one teeth about its periphery, it being noted that one of the teeth, i. e., the tooth 32, is of double length. Preferably, there are fifty-two holes 3! in the circular series of holes in the ratchet wheel 3%. This ratchet wheel 30 is apertured at its center and is mounted on the shaft if! for free rotation thereon immediately above the disc 22. When thus mounted, the paWls 2t, 2t and till engage the teeth on the periphery of the wheel 39, it being obvious that oscillation of the disc 22 and its associated arm 23 in a counten-clockwise direction, will cause a step-by-step rotation of the ratchet wheel 31'] and that the spring-pressed pawls 28 and 29, while permitting such rotation, will prevent clockwise rotation of said ratchet wheel.

Superimposed upon the ratchet wheel 39 is a thin, flat disc 33 of greater diameter than said ratchet wheel, said disc having at its center an aperture through which the shaft i0 extends. This disc 33 is provided with one or more apertures located at a point or points remote from the center of said disc and overlying the circular series of holes 3! in the underlying ratchet wheel, and a pin 34 is passed through each aperture in the disc 33 and enters one of the holes 3! in the ratchet wheel 38, whereby the said disc is caused to rotate with said ratchet wheel about the shaft ill. The upper face of the disc 33 is inscribed with two concentric rows of letters 35 and 35, there being, preferably, fifty-two letters in each concentric row. The outermost row 35 has alter- G; M, O, Q, S, U, W and Y, i. e., with progressively "alternate letters of two alphabets each beginning with A and similar series of thirteen spaces 39 above referred of a diameter nate inscribed with the letters A, C, E,

spaces 3 ending with Y. The alternate spaces 38 intermediate the alternate spaces 31 above referred to, are inscribed with the letters Q, S, K, M, E, Y, G, I, C, W, A, 0, U, Q, S, K, M,'-E, Y, G, I, C, W, A, O and U, i. e., with two nermost row 36 has alternate spaces 39 inscribed with the letters N, 0, P, Q, R, s, T, U, v, W, X, Y, Z, N, O, P, Q, R, S, T, U, V, W, X, Y and Z, i. e.; withtwo similar series of thirteen letters each'beginning with N and ending with Z. The alternate spaces 40 intermediate the alternate to, are inscribed with the letters Z, X, V, N, Y, O, Q, P, S, T, R, U, W, P, S, T, R, U and W, i. e., with two similar series of thirteen letters each.

' Mounted above the disc 33 is a thin, flat disc 4| corresponding to the inner diameter of the innermost row 36 of letters inscribed on the upper face of the disc 33, the disc 4| having at its center an aperture through which the upper end of the shaft! extends. The disc 4| is keyed or otherwise secured to the shaft |0 so as to rotate therewith. Extending radially from the periphery of the disc 4| are a plurality of spaced tabs 42, preferably twenty-six in number, these tabs being inscribed with the letters A, B, D, c,- F, E, G, H, I, J, K, L, M, A, B, D, 0,1 E,

G, H, I, J, K, L and M, i. e., with two similar series of thirteen letters each.

e As a convenient means for effecting manual operation of the machine of my present invention, I provide an operating lever 43 having at its forward, free end a key 43 by means of which the said lever may be manually depressed. The inner end of the lever 43 is mounted on a horizontal pivot 44 which extends between, and is secured to, a pair of upstanding lugs 45 mounted on the base 2. A tension spring 46 extends between the lever 43 and a fixed point on the inner surface of the side wall 3 and tends to maintain the lever 43 in its normal position shown in Fig. 8. A bell crank lever 41 having a relatively long arm 48 and a relatively short arm 49 is pivotally mounted on the base 2 by means of a suitable bracket 50 rigidly secured to said base. A rod. or link extends between the upper free end of the arm 48 and the arm 23 of the disc 22 whereby oscillation of the bell crank lever 41 will impart oscillation to the disc 22 and to the parts carried thereby. As a convenient means for imparting oscillatory movements to .the bell crank lever 41, the said lever is connected to the lever 43 by means of a pivoted link 52, so that as the lever 43 is moved downwardly the bell crank lever 41 will be rocked in a counterclockwise direction as viewed in Fig. 8, and, through the rod or link 5|, will impart a like movement to the lever arm 23 and its associated disc 22, it being obvious that as the lever 43 is released the tension spring 46 will'return the said lever to the normal position and that such movement of the said lever, through the link 52, will rock the bell crank lever 41 in a clockwise direction as viewed in Fig. 8.

An important feature of my present invention resides in means whereby the extent of the oscillatory movement imparted to the disc 22 by the operating lever 43 is successively and progressive- 1y varied. In the form of my invention shown in Figs. 1 to 10, inclusive, I mount a shaft 53 between spaced, upstanding brackets .54 and 55seletters each. The incured to the base 2. Upon the shaft 53, I-mount a ratchet wheel 56, this ratchetwheel preferably having an odd number of teeth, say nineteen. Adjacent this ratchet wheel 56, I mount on the shaft 53 an indicating wheel 51, having a series of consecutive numbers arranged on its periphery and corresponding to the number vofteeth on the ratchet wheel 56. As shown-in Figs. '7 and 9 the numbers on the peripheryof the disc or'wheel 51 run consecutively from'one to nineteen, as there are nineteen teeth on the ratchet wheel 56. I next mount on the shaft 53 three discs .56, 59 and 169, the detailed construction of these discs being shown, respectively, in Figs. 2, 3 and 510i the accompanying drawings. Eachof these discs is provided with a centrally-located aperture'of a diameter slightly exceeding the diameter of the shaft '53 and the periphery of each disc is provided with segmental cut-out portions of varying lengths to form variously spaced and variouly dimensioned stop surfaces or shoulders 6| ofsegmental configuration. Each of the discs 56, 59 and 69 is provided with a circular series of holes 62, each series corresponding in number to the number of teeth on the ratchet wheel 56, i..e., in the present instance, there is a total of nineteen holesin each of the series in each of the three discs. The ratchet wheel 56 and the indicating wheel or disc 51 are each provided with an aperture located a, distance from their respective centerscorresponding to the radius of the circular series of holes 62 in the discs 56, 59 and 69. After 4 on'the shaft 53 a second indicating wheel or disc 64 having a series of consecutive. numbers arranged on its periphery and adjacent this wheel or disc 64 I mount on the wheel 65, this ratchet wheel. 65 havingan odd number of teeth,- say fifteen, in which instance the series of numbers on theperiphery of the wheelor disc 64 will run consecutively from one to fifteen. The wheel or disc-64 andratchet wh'eel65 are secured together for simultaneous rotation on the shaft53 by means of'a'pin 66 which passes through said wheel or disc and ratchet wheel, it being understood that the group comprising members 56, 51, 58, 59 and 69and the group comprising members 64 and 65 are capable of independent rotation on the stationary, shaft 53. Disc 64, like discs 58, 59 and 69, is provided with egmental cut-out portions to provide peripherally-spaced stop surfaces or shoulders 6| of segmental configur tion, the series of numbers above referred to being applied to said stop surfaces or shoulders and to the exposed surfaces between said stop surfaces or shoulders. I

In orderto efiect rotationof the members 56, 51, 58, 59 and 60 on the shaft 53, l mo'u nt on said shaft immediately adjacent the ratchet shaft 53 a secondratchet ratchet wheel 56. A second, spring-pressed pawl II is mounted on a fixed part of the casing and has one end engaging the teeth of the ratchet wheel 56 and its opposite end connected by a tension spring 1| to a fixed point on the casing, the arrangement being such that the pawl 18 will permit clockwise rotation of the ratchet wheel 58 and the members secured thereto for rotation on the shaft 53 but will prevent counter-clockwise rotation of said ratchet wheel and its associated members.

In order to effect rotation of the members 64 and 65 on the shaft 53 independently of the rotation of the ratchet wheel 56 and the members secured thereto, I mount on said shaft immediately adjacent the ratchet wheel 65 an upstanding arm 12 having its lower apertured end pivotally mounted on said shaft and having a pawl 13 pivotally mounted on its side near its upper or free end in a position to overlie the ratchet wheel 65. A tension spring 14 connects one end of said pawl to a fixed point on said arm, which spring tends at all times to urge the opposite end of said pawl into engagement with the teeth on the periphery of the ratchet wheel 65. A second, spring-pressed pawl 15 is mounted on a fixed part of the casing and has one end engaging the teeth of the ratchet wheel 65 and its opposite end connected by a suitable tension spring to a fixed point on the casing, the arrangement being such that the pawl 15 will permit clockwise rotation of the ratchet wheel 65 and its connected indicating wheel or disc 84 but will prevent counter-clockwise rotation of said ratchet wheel and indicating wheel or disc.

As a convenient means for effecting actuation of the pawls 88 and 13 to effect a progressive, step-by-step rotation of the ratchet wheels 56 and 65 and their associated parts on the shaft 53, I connect the upper or free end of the arm 61 by means of a rod or link 16, to the upper or free end of an upstanding lever arm 11 keyed or otherwise fixed on a shaft 18, which shaft is journalled for rotation in spaced, upstanding brackets 19 and 80 secured to the base 2 of the machine near the front thereof, and I connect the upper or free end of the arm 12 by means of a rod or link 8 I to the upper or free end of an upstanding lever arm 82 keyed or otherwise fixed on the shaft 18. I key or otherwise fixedly secure to the end of the shaft 18, a lever arm 83 which extends substantially horizontally of the machine and substantially at right angles with respect to the upstanding lever arms 11 and 82, the lever arm 83 having a pin or abutment 84 extending laterally from its outer or free end and located in the path of the operating lever 43, the arrangement being such that as the said operating lever approaches its lowermost position, it will contact the pin or abutment 84 and will force the outer or free end of the lever arm 83 downwardly, thus causing a, clockwise movement of the shaft 18 as viewed in Fig. 8, and, through the lever arms 11 and 82 and the rods or links 16 and 8|, causing a corresponding movement of the arms 61 and 12 and of the pawls68 and 13 carrie thereby, which results in the ratchet wheels 56 and 65 and their associated parts being moved a distance equivalent to the spacing between each of the teeth on the periphery of the respective ratchet wheels.

In the modified form of my invention shown in Figs. 11 to 14 inclusive, the construction and operation of certain of the parts included therein is substantially the same as that shown and described in connection with that form of my invention shown in Figs. 1 to 10 inclusive, except insofar as relates to the mechanism for varying the extent of movement or oscillation of the disc 22 and its associated parts. In Figs. 1 to 10, inclusive, the means for determining the extent of oscillation of the disc 22 is mounted on a horizontal shaft, which construction necessitates the provision of a casing having a substantial height. In the modified form of my invention shown in Figs. 11 to 14, inclusive, the means for determining the extent of oscillation of the disc 22 is rel- 'atively fiat and is mounted on a relatively short, vertical shaft so that it is possible to make the machine relatively flat and to enclose the same in a relatively shallow casing, thu greatly reducing the size of the machine. The means for imparting step-by-step rotation to the ratchet wheel [2, movement of the disc 22, and its associated arms 23 and 24, step-by-step rotation of the ratchet wheel 30, and rotation of the lettered discs 33 and 4| with respect to the series of fixed,

lettered tabs 9, may be the same as those shown and described in connection with Figs. 1 to 10, inclusive, a showing of such means having been omitted from Figs. 11 and 12 for the sake of simplicity and cleamess of illustration, it being noted, however, that in the form of my invention shown in Figs. 11 and 12, I have omitted the operating lever 42, bell crank lever 41 and link 5|, and that the lever arm 23 is extended through an arcuate slot cut through the upper edge of the curved end wall 5 of the casing. The extended lever arm 23 has connected thereto a tension spring 86, the opposite end of which is connected to a fixed point on the side wall 3 of the casing, this spring urging said lever arm in a clockwise direction as viewed in Fig. 11.

As a means for determing the extent of oscillation of the lever arm 23 and its associated parts, I mount on the base 2 of the casing a stationary, vertical shaft 81 preferably of stepped formation as shown in Fig. 12. This shaft may be conveniently secured to the base 2 by means of a bolt 88 which passes through an aperture in said base and threads into the lower end of said shaft. The shaft 81 has a threaded upper end 89 which passes through an aperture in the inner end of a bar or bracket 90 secured to the side wall 4 of the casing, a nut 9| being threaded on the upper end of said shaft and above the said bar or bracket. Arranged upon the shaft 81 is a radially extending arm or lever 92 on the outer end of which is a spring-pressed pawl (not shown) which engages the teeth on a ratchct wheel 93 also mounted. on said shaft. The arm 92, the pawl carried by said arm, and the ratchet wheel 93, correspond, respectively, in function and operation, to the arm 12, pawl 13 and ratchet wheel 65 previously described, the ratchet wheel 93 having an odd number of teeth, say IS, on its periphery. A spring-pressed pawl 94 is mounted on the base 2 of the casing and functions to prevent clockwise rotation ofthe ratchet Wheel 93 as viewed in Fig. 11. A disc 95 is mounted on shaft 81 immediately above the ratchet wheel 93 and is provided on its upper face with a series of numerals ranging from one to seventeen as indicated in Fig. 11. A relatively thin spacing disc 96 is mounted on shaft 81 immediately above disc 95, and above said spacing disc is mounted on said shaft a disc 91, the shape and configuration of which is best shown in Figs. 11 and 14, it being noted that this disc is provided with segmental cut-out portions to the arm 92 and engagement of its spring-pressed pawl with the teeth on the ratchet wheel 92 effecting such rotation.

A disc I is next mounted on the shaft 81, the shape and configuration of which is best shown in Fig. 13, it being noted that this disc is provided with a series of segmental cut-out portions of varying lengths and depths to form variously-spaced and variously-dimensioned stop surfaces or shoulders IOI of segmental configuration. The disc I00 is provided with a circular series of holes I02, preferably nineteen holes comprising the series. Above the disc I00 and on theshaft 81 there is next mounted a relatively thin disc I03 on the upper surface of which is arranged a series of numerals varying from one to nineteen as shown in Fig. 11. A ratchet wheel I04 is next mounted on the shaft 81, this ratchet wheel having a total of nineteen teeth on its periphery, which teeth are engaged by a springpressed pawl I carried by an arm I06, the inner end of which is mounted for oscillation on shaft 81 immediately below the arm or bracket 90. A pin I01 is passed through the ratchet wheel I04, disc I03 and through any one of the holes I02 in disc I00 so that these members rotate about the shaft 81 as a unit, oscillation of the arm I05 and engagement of the pawl I05 effecting such rotation. A spring-pressed pawl I08 is mounted on the underside of the arm or bracket 90 and functions to prevent clockwise rotation of the ratchet wheel I04 as viewed in Fig. 11. The arm I06, the pawl I 05, and the ratchet wheel I04, correspond, respectively, in function and operation, to the arm 61, pawl 68 and ratchet whee1 50 previously described.

Asa convenient means sive, step-by-step rotation of the ratchet wheels 93 and I04 and their associated parts about the shaft 81, I connect the outer I00, by means of a rod or link I09, to the outer end of a lever arm IIO keyed on a vertical shaft III journaled for rotation in a suitable bearing (not shown) mounted on the base 2 near the side 3 of the casing. A lever arm H2 is also keyed on shaft III and is disposed at an angle of approximately 90 degrees with respect to arm H0, this lever arm II2 having at its outer end an apertured' lug H3 which slidably engages a rod or link II4, one end of which is connected it being noted that the outer end of said rod or link is provided with an enlarged end portion II5 for a purpose to be hereinafter described. A second arm (not shown) corresponding structurally on shaft I I I at the approximate level er the arm 92 and is connected to the outer end of the arm 92 by means of a rod or link (not shown) corresponding structurally to the rod or link I09. In order to limit the clockwise movement of the arms IIO keyed on the shaft III as said arms move from the dotted line position shown in Fig. 11 to the full line position shown therein, 1 mount a stop II6 on the base 2 of the casing in a position to be contacted by the arm IIO which moves immediately above said base and which is connected to the arm 92, a suitable tension spring (not shown) being connected to the lowermost of the arms IIO and to a fixed point on the base 2 to resiliently urge said arm into contact to the arm 23,

for effecting progres- I end of the arm to the arm I I0, is also keyed with said stop. It will be understood, of course, that as the lever arm 22 shown in Fig. 11 is moved in a counterclockwise direction as viewed in said figure, it contacts, during the latter part of such movement and prior to its contact with the end of the slot 85, an abutment-I4 carried by an arm I8, and moves said arm It in acounterclockwise direction and, through a pawl I6, causes a progressive, step-by-step rotation of a ratchet wheel I2 and of a disc 40, all of these parts being adequately disclosed and described in connection with that form of my invention shown in Figs. 1 to 10, inclusive.

In Figs. 15 to 21, inclusive, I have shown a further modification of my present invention,

, numerous of the parts of which correspond in construction,

function and operation to the forms of my invention previously shown and described. particularl the dorm of modification comprises a ratchet 88' which,

form shown and-described in connection with Figs. 11 and 12. This vertical shaft 81' extending upwardly from the base 2 of the casing and secured thereto, and having mounted thereon, in the order named, an arm 92-; a like the ratchet 93 has, say, seventeen teeth on its periphery; a disc 95' provided on its upper face with a series of numerals ranging from one to seventeen as indicated in Fig. 15; a relatively thin spacing disc 90'; and a disc 91', the shape and configuration of which is best shown in Figs. 15 and 20, it being noted that this disc is provided with segmental ,cutout portions to provide peripherally-spaced stop surfaces or shoulders 88'. A pin (not shown, but corresponding to the pin 89 shown in Fig. 12)

is assed through aligned apertures in the ratchet H 19 and 17, it being noted that the discs H1, I-I 8 and II9 are of progressively decreasing diameter and that these three discs are each provided a that each of the with a series of segmental cut-out portions of varying lengths and depths to form variouslyspaced and variously dimensioned stop surfaces or shoulders I2I, I22 and I23, respectively, and

discs II1,-II8 and ll9 is provided with a circular series of nineteen holes I24, I25 and I20, respectively. The disc I20 is provided with a hole I21 adapted to be aligned with selected holes of the underlying series of holes I20, I25 and I24 in the discs II9, II8,and II1, respectively, this disc I20 having arranged on its upper face, acircular series of numerals ranging from one to nineteen. I next mount on the'shaft 81' a ratchet wheel I04, this ratchet wheel having a total of nineteen teeth on its periphery, which teeth are engaged by a springpressed pawl I05 carried by an arm I05, the inner end of which arm is mounted for oscillation on shaft 81' immediately below the arm or bracket A nut 9| is threaded on the upper end of the shaft 81 immediately above the arm or bracket 90'. A pin (not shown but corresponding' to-the pin ,I0I shown in Fig. 12) is passed through a hole in the ratchet wheel I04 through hole I21, and through one of the holes in each circular series of holes I26, I25 and I24 in discs H9, H8 and IIL respectively, so that these members rotate about the shaft 81 as a unit, oscillation of the arm Hi6 and engagement of the pawl I 65' with the teeth on theratchet wheel I84 effecting such rotation. The arm I86 is connected by a rod or link I59 to an arm such as the arm I I of Fig. 11, it 'being'understood that a similar rod or link (not'shown) is connected to the arm 92" and that said rod or link is connected to an arm such as the lowermost arm IID of Fig. 11, the arrangement being such that the arms 92' and I06 are oscillated to effect a progressive, step-by-step rotation of the ratchets 93' and I84, respectively. Suitable spring-pressed pawls 94 and I08 are mounted on the base 2 and on the underside of arm or bracket 90', respectively, and function to prevent counterclockwise movement of the ratchets 93' and I04, respectively, as viewed in'Fig. 15.

Suitable indicating marks, such as the arrows I28 on cover 1 (see Fig. 1), I29 cn'platformG (see Fig. 8), I38 on the edge of the double tooth 32 (see Fig. 8), I3I and I32 on pawls 68 and 13, respectively (see Fig. 9), I33 on base 2 (see Fig. 11), and I34 on base 2 (see Fig. 15), are provided to cooperate with letters r numerals on the peripheries or upper surfaces of certain of the discs in a manner to be hereinafter described.

Having thus described the construction of the 7 several forms of my invention presented herein, I will now describe the manner in which these devices are operable to obtain or accomplish the objects of my present invention. Referring to Figs. 1 to 10, inclusive, I first assemble on the left-hand end of shaft 53, as viewed in Fig. 7 and in the order named, ratchet 56, indicating disc 51, and discs 58, 59 and '60, and then pass pin 63 through the aligned holes in ratchet 56 and disc 51 and through one of the holes in each of the circular series of holes in 'discs 58, 59 and 60. I next assemble onthe right hand end of shaft 53, disc 64, followed by ratchet 65, and then pass pin 66 through the hole in ratchet 65 and through one of the holes of the circular series of holes in disc 64. Shaft 53 and its associated discs and ratchets just described, are now mounted in the machine and occupy the position shown in Figs. 8 and 9. Pawls 68 and I3 engage, respectively, the ratchets 56 and 65, whereby oscilla tion of the arms 61 and 120m which said pawls are mounted, will eflect progressive, step-by-step rotation of said ratchets and the parts connected thereto, this rotation being of different arcuate increments, due to the fact that the ratchet 56 has nineteen teeth, whereas the ratchet 65 has only fifteen teeth. When thus arranged, it will be obvious that depression of the operating lever 43 will cause said lever to strike the pin 84 on lever arm 83, which will depress arm 83 to cause limited rotation of the shaft I8, which will advance ratchets 56 and 65 a distance equivalent'to the spacing of the teethlon said ratchets, this being effected through the medium of upstanding lever arms 11 and 82, rodsor links '16 and 8| and pawls 68 and 13. When operating lever 43 is released and is pulled upwardly by spring '46, the shaft 18 and the parts carried thereby will be returned to their normal position by the spring I35 which extends between bracket 54 and an upstanding lever arm I36 keyed on shaft I8, the pawls I8 and I5 preventing reverse rotation of the ratchets 56 and 65 durin such return movement.

The disc 22 is placed on theshaft I6 and the arm 23 of said disc is connected to the'arm' 48 of bell-crank lever 41 by means of rod or link gaseous 5I, itbeins obvious that as the'op'erating lever 43 is'depressed, the connection 52 between said lever and arm 49 of bell-crank lever 41 will-cause the arm 23, disc 22 and arm 24 to move in a counterclockwise direction as viewed in Figs. 1 and 9. As the arm 28 approaches the end of its counterclockwise movement with respect to the slot IE, it contacts abutment I4 on lever arm I3 and moves this arm in a counterclockwise direction until said arm abuts the fixed stop 2|. During this movement of the lever arm I3 between stops 28 andZI, the pawl I6 carried on said arm and which engages the teeth on ratchet wheel I 2, causes a progressive, stepby-step counterclock wise rotation of said ratchet wheel and of the shaft III to which said ratchet wheel is keyed or otherwise secured.

By reference to Fig. 9, it will be noted that the depending portion 25 of arm 24 occupies a position where it abuts the inner surface of the indicating disc 57, this position representing the limit of the clockwise movement of said arm 24, the said depending portion 25 having reached this position by passing through the segmental spaces between the radial stop surfaces or shoulders on the discs 64,68, 59 and 58. When operating lever 43 is depressed, the disc 22 and arms 23 and 24 carried thereby, are moved in a counterclockwise direction, during'which movement the depending portion 25 passes through the spaces between the radial stop surfaces or shoulders on the discs 64, 60, 59 and 58 and reaches a position where it overlies the ratchet 65. When this position is reached, the operating lever 43 contacts the pin 84 on lever arm 83 and, through upstanding lever arms 1'! and 82, rods or links I6 and BI and pawls 68 and I3, causes the ratchets 56 and 65 and thc parts'carried thereby to be advanced a distance equivalent to the spacing of the teeth on the respective ratchets, it being noted that the depending portion 25 of lever 24 in no way interferes with this movement, due to the fact that it has been moved to a position beyond the end of the disc 64 and above the ratchet 65. When the operating lever is released, the disc 22 and arms 23 and 24 carried thereby move in a clockwise di rection, but the depending portion 25 of arm 24 strikes against one of the stop surfaces or shoulders on one of the discs 68, 59, 60 or 64, which stop surface or shoulder has been moved into the path of said depending portion by the progressive, step-by-step rotation of said discs. Hence, the clockwise or return movement of the disc 22 andits arms 23 and 24 is determined by contact between depending portion 25 and one of the shoulders on the series of discs 58, 58, 68 and 64. Due to the irregular spacing of these stop surfaces or shoulders and the differential rotation of the fifteen toothed ratchet 85 as compared with the rotation of the nineteen-toothed ratchet 56, it will be obvious that the limit of the clockwise or returnmovement of disc 22 and its arms 23 and 24 is constantly varied and that such limit determines the extent of the'counterclockwise movement imparted to the lever arm 28 and the pawl 26 carried thereby. This means forprogressively varying the counterclockwise movement of the arm 23 and its pawl 26, constitutes an important feature of my present invention.

' In the form of my invention shown in Figs. 11 to 14 inclusive, the variation of the clockwise or return movement of the lever arm 23 is effected by contact between the depending portion 25 of arm '24 with the stop surfaces or shoulders 98 and IIJI on the discs 81 and I06, respectively.

. clockwise movement of against one of the stop which stop surfaces or shoulders are formed on said discs by the variously-spaced and variouslydimensioned segmental cut out portions of said discs. As the lever arm 23 of this form of my invention is moved in a counterclockwise direction as viewed in Fig. 11, the disc 22 and arms 23 and 24 are moved to positions shown in dotted lines in said figure and wherein the depending portion 25 is out of the path of movement of the stop surfaces or shoulders 98 on disc 91 whereby said disc and its associated parts may be rotated without interference by the depending portion 25. It will be noted that during the initial counterclockwise movement of the arm 23, the rod or link II4 slides within the apertured lug II3 until the enlarged portion II5 on said rod or link contacts said lug. At this point in the operation of the mechanism the depending portion 25 of arm 24 has been moved to a position represented by dotted lines in Fig. 11. Continued counterthe arm 23 causes said arm to contact abutment I4 to rotate ratchet I2 and shaft I0 a distance equivalent to the distance between the teeth on ratchet I2, and also causes the rod or link 4 to move the arms IIO on shaft III in a counterclockwise direction, which movement, through links I09, arms 92 and I06, and pawls I05, causes the ratchets 93 and I04 andthe parts carried thereby to be advanced a distance equivalent'to the spacing of the teeth on the respective ratchets. When the operating lever 23' is released, the disc 22 and arms 23 and 24 carried thereby move in a clockwise direction, until the depending portion 25 of arm 24 strikes surfaces or shoulders 98 or IN on the discs 91 and I00, respectively, which stop surface or shoulder has been moved into the path of said depending portion by the progressive, step-by-step rotation imparted to the discs 91 and I00. Hence, the clockwise or return movement of the disc 22 and its arms 23 and 24 is determined by contact between depending portion 25 and one of the shoulders 98 or IOI. Due to the irregular spacing of shoulders 98 and IM and the difierential rotation of the seventeentoothed ratchet 93 as compared with the rotation of the nineteen-toothed ratchet I04, it will be obvious that the limit of the clockwise or return movement of disc 22 and its arms 23 and 24 is constantly varied and that the variously-positioned and variously-dimensioned stop surfaces or shoulders 98 and IN determine the limit of the clockwise or return movement of disc 22 and its arms 23 and 24 and, hence, determine the extent of the counterclockwise-movement imparted to the lever arm 23 and pawl 26 carried thereby. It will be obvious that in this form of my prevent invention, the disc 91 corresponds 1 in function and operation to the disc 64 of the mechanism shown in Figs. 4, 7 -and 9, and that the disc I00 corresponds in function and operation to the combined discs 58, '59 and 60.

In the form of my invention shown in Figs. 15 to 21, inclusive, the disc 91' corresponds in function and operation to the disc 64 and disc 91 previously described. In this form of my invention, however, the variously-positioned and variously-dimensioned stop surfaces or shoulders are not formed on a single disc such as the disc I00 of Fig. 13, but are provided on three separate discs II1, H8 and H9 of progressively decreasing diameter as illustrated in Figs. 18, 21' and 19, respectively. The operation of this modified form of my invention will, it is believed, be obvious from the presently-presented description of teeth on the respective ratchets.

the operation of the mechanism shown in Figs; 11' to 14, inclusive. Suflice it'to say that actuation of the lever arm 23 initially moves the de-J pending portion 25 from the position shown in Fig. 15 to a position where said depending portion is out of the path of movement of the stop surfaces or shoulders 98' of disc '91, whereupon arms I06 are given a clockwise movement and; through pawls I05, cause a clockwise rotation of ratchets 93' and I04 and of the parts carried thereby, a distance equivalent to the spacingot when the operating lever 23 is released, the 23 and 24 move in a clockwise direction until the depending portion 25 strikes one of the stop sur-' faces 98', I2I, I22 or I23, which stop surfaces or shoulders are successively and to widely varied degrees, moved into the ing portion to determine the extent of the clockwise or return movement of the disc 22 and its associated parts. Any preferred form 01 mech-'' anism may be provided between the manually operated lever arm 23 and the arms I08'- for transmitting movement from said arm 23 and arms I06 to effect the progressive, step-by-step, difierential rotation of the ratchets 92' and I04i It will be obvious from the above that it' is possible to assemble the discs 58, 59 and 50 to their respective ratchets in an almostinflnite number of relationships, due to the presence of the circular series of holes 62 provided insaid discs, and that the single disc I00, and the pinrality of discs II1, H8 and H9 may likewisebe assembled with their respective ratchets I04 and I04. Hence, the clockwise movement 22v may be varied to a very great extent by vthe innumerable ways in which the discs 58, '59 and 60, or the single disc I00, or the discs I'I1,"IIO

and H9, are assembled. Further variation is possible by varying the number of teeth, 'andthe relationship between the number of teeth, on the ratchets 56 and 65, 93 and I04, and 93 andIIIl'. The ratchet wheel 30 is placed on shaft I0 in a position wherein the indicating arrow I30on the edge of the double tooth 32 is aligned with the indicating arrow I29 on the platform Ii, with pawi 26, 28 and 29 engaging the teeth on the periphcry of said ratchet. Disc 33 is now placed on shaft I0 and the pin 34is inserted through anapertli fe in said disc and into any one of the holes lL-of the circular series of holes in said disc. Disc 4| is now placed on shaft I0 and is keyed or otherwise secured. to said shaft 'for rotation therewith; Cover 1 is then secured to the top of the casing and occupies the position shown in Fig. 1. 'When thus assembled, the machine is ready for the coding or decoding of messages or-other data. When it is desired to send a message, the operator, after ascertaining that the indicating mark I30 is in alignment or registration with the indi cating'mark I29, makes a note of the number on disc 51 which is opposite and a note of the number on disc 54 which is opposite the indicating mark I32, these numbers, in the setting shown in Fig. 9, being "9 and "7, respectively. He then makes a note of the. first three letters which are exposed between the first four stationary tabs 9 adjacent the indicating mark I28 on cover 1 and reading in a' counterclockwise direction with respect to indicating mark I28, i. e., between the letters Bfif D,'f F? and ,H, these letters, in the setting shown-in Fig. 1, being K, "M? and 0. He next makes a note of the letter on the series of tabs 42"on disc 4|, which letter is radiall inward with re;

disc 22 and arms path of the said depend'- oi the disc the indicating mark j I3 I",

spect to the tab 9jon which the letter B appearsyand, which, in the setting shown in Fig. 1, is the letter H. The code message will thereforestart with the key numerals 9 and 7, followed by the key letters K, M, O and HJ' i. e., 97KMOH. Assuming that the message to be coded is Claims allowed, the operator locates the letter C on the series of letters appeering. on the outermost series comprising the stationary tabs 9 and the outer series 35 of disc 33, which combined series may constitute the letters of the clear text. It will be noted that the letter appears radially inward of the letter C." and, hence, O, which is the code or cipher letter, will constitute the first letter of the actual code message. The lever 43 is then depressed by the-operator, which depressing swings the depending portion 25 of lever 24 from its position shown inFig. 9 too, position clear of the discs 51', 58, 59, 60 and 64, continued movement of the operating lever 43 causing the ratchet wheel 30 and its associated disc 33 to be rotated for a distance corresponding to five of the teeth on said ratchet, and also causing the ratchet I2, shaft I0 and disc M to be operated for a distance corresponding to one of the teeth on said ratchet I2. The relationship between the letters of the clear and code or cipher text is therefore materially changed, due to the rotation of the discs 33 and M relative to thestatio nary lettered tabs 9 and relative to each other. Upon the release of lever 43, the disc 22 and its arms 23 and 24 swing in a clockwise direction as viewed in Fig. 9, but this movement is arrested by contact of the depending portion 25 with one of the stop surfaces or shoulders BI on disc 64. The operator then locates the letter L on the clear text series and finds that the code or cipher letter radially inward from this letter is the letter U" which letter will constitute the second letter of the actual code message. Operating lever 43 is again depressed, which depressing results in the rotation of ratchet 3E! and disc 33 a distance corresponding to one of the teeth on said ratchet, and also causes the ratchet I2, shaft I 0 and disc M to be operated a distance corresponding to one of the teeth on said ratchet I2. This again changes the relationship between the letters of the clear and code or cipher text. Upon the release of the lever 43, the disc 22 and its arms 23 and 24 swing in a clockwise direction as viewed in Fig. 9 until this movement is arrested by contact of the depending portion 25 with one of the stop surfaces EI on the disc 60. The operator then locates the letter A on the clear text series and finds that the corresponding letter on the code or cipher series is N, which letter will constitute the third letter of the actual code message. Upon next depressing the lever 43, the ratchet 30 will be moved a distance corresponding to three of the teeth on said ratchct. as the return movement of the disc 22 and 'its arms 23 and 24 had been arrested, as the result of the previous depression of the lever 43, by contact with the stop surface 6| of disc 59. The operation of coding the message is completed b repeated depression of the operating lever 43 and by translating the letters of the actual message from the clear text to the code or cipher text. When such translation is completed for the message Claims allowed, let it be assumed that the com- Dlete coded message will read Q'YKMOH OUNPMK GJNUBYI.

This code message is transmitted by writing, phone or other means of communication, and

when said message is received by an authorized recipient supplied with a like machine, it is a comparatively easy matter to decode or decipher the message. Assuming that the coding and decoding machines are similarly arranged, i. e., that the corresponding ratchets in the two machines have the same number of teeth, that the discs and ratchets are similarly arranged on shaft 53 and that the discs 33 are similarly arranged on ratchets 30, the recipient of the code message above given by way of example, sets his machine in accordance with the key numerals and letters constituting the initial part of the code message, i. e., he brings the indicatin marks I29 and I30 into alignment or registration, and sets the indicating disc 57 so that its number 9 is opposite the indicating mark I3I and the number "7 is opposite the indicating mark I32 on pawls 68 and 13, respectively. He next sets the disc 33 in accordance with the key letters KMO contained in the initial portion of the code message, i. e., he arranges the disc 33 so that the letters K, M and 0 appear on the outer circle of letters between the letters B, D, F and H on stationary tabs 9. Finally, he moves the disc 4| until the letter H on tabs 42 is arranged radially inward from the indicating mark I28 and the letter B on stationary tabs 9. His machine is now set for a simple and accurate decoding or deciphering of the code message. He first refers to the letters of the code or cipher text and locates the letter "O" which appears on the inner series of letters 39. He finds that the letter on the outer series of letters 31 which is radially outward with respect to said letter 0, is the letter C, and he writes this down as the first letter of the decoded message. He then depresses the operating lever 43 which moves the ratchet 30 and its associated disc 33 and also moves the disc 4|, the extent of movement of said disc 33 being a distance corresponding to five of the teeth on said ratchet, and the extent of movement of said disc 4I being a distance corresponding to one of the teeth on the ratchet I2. Hence this first depression of lever 43 during the decoding or deciphering operation corresponds to the first depression of said lever made by the operator of the coding machine during the preparation of the code message in the manner above described, i. e., the letters of the several series will occupy on the recipient machine, the same identical relation which said letters occupied 0n the senders Or transmitters machine at this stage of the coding operation. By locating the letter U on the innermost or code series of letters the recipient will readily ascertain that the corresponding letter on the outer or clear text series is L and, hence, L will constitute the second letter of the decoded message. Lever 43 is again depressed which depressing results in the rotation of ratchets 30 and disc 33 a distance corresponding to one of the teeth on said ratchet and also cause ratchet I2, shaft I0 and disc M to be operated a distance corresponding to one of the teeth on said ratchet I2. By locating the letter N on the innermost or code series of letters, the recipient will readily ascertain that the corresponding letter on the outer or clear text series is A and, hence, A will constitute the third letter of the decoded message. The operation of decodin or deciphering the message is completed by repeated depression of operating lever 43 and by translating the letters of the message from the code or cipher text to the clear text in the manner above described. When such translation is ther variations in completed, the actual decoded or deciphered message will read Claims Allowed.

The methods of coding and decoding messages in the mechanisms shown in Figs. 11 to 14, inelusive, and in Figs. 15 to 21 inclusive, are substantially the same as those described in connection with Figs. 1 to 10, inclusive, the important difference in the constructions involved being restricted, essentially, to the mechanism which limits or restricts the return movement of the disc 22 and its associated parts and which thu determines the extent of the movement of arm 23 and hence the extent of rotation of the ratchet 30 and disc 33. In Figs. 1 to 10, inclusive, the variouslypositioned and variously-dimensioned stop surfaces or shoulder are arranged on Vertically-disposed discs 58, 59, 60 and 64, whereas in Figs. 11 to 14, inclusive, the stop surfaces or shoulders are arranged on horizontally disposed discs 91 and I mounted on vertical shaft 81, the disc 91 corresponding in function and operation to the disc 64', and the disc 100 corresponding in function and operation to the discs 58, 59 and B0. In Figs. to 21, inclusive, the variously-positioned and variously-dimensioned stop surfaces are arranged on horizontally disposed discs 91', H1, H8 and H9, it being apparent that discs 91', H1, H8 and H9 correspond in function and operation to discs 64, 58, 59 and BI], respectively.

In all forms of the invention, the various discs and the variously toothed ratchets which drive these discs so limit or restrict the return or clockwise movement of disc 22, its arms 23 and 24 and its pawl 26, that the counterclockwise movement or throw imparted to said disc upon successive depressions or movements of the operating lever, is constantly varied to effect, to a very great extent, the successive and progressive movement of one set or sets of the text elements with respect to'the other set or sets. The relationship of the various discs on their respective shafts, and the relationship of the various discs to each other, may be readily varied or changed to provide furthe extent of the successive movements or rotary increments imparted to the lettered discs 33 and 4|. The ratchets which drive the discs may be replaced or interchanged to effect a further variation in the progressive movement ofdiscs 33 and 4|. Discs 9'! and I00 may be inverted on shaft 81 to thus effect'variations in the order or sequence of the variable rotary increments imparted to discs 33 and ll, similar variations, but to a still greater extent, being possible by inverting the discs 91, H1, H8 and H9 on the shaft 8'1. Discs, such as 58, 59, 60, 64, 91, 91', I00, H1, H8 and H9 may be made up in sets in which the stop surfaces or shoulders are variously arranged and variously dimensioned, and by substituting one or more of these discs for one or more of the discs previously used,

an exceedingly great number of different combinations are readily obtainable. The position of the disc 33 with respect to the ratchet 39 may be readily varied by removing the pin 34 from one of the holes 3| of the series in ratchet 30, rotating the said disc with respect to said ratchet, and inserting pin 34 in one ofthe other holes 3| of said series. The provision of one or more blank teeth 32 on ratchet 30 also assists in obtaining the varied movements of the several sets of text elements, it being obvious that when the nose of pawl 26 rests on the blank tooth or teeth 32, said pawl will slide along the surface of said tooth without imparting rotation to ratchet 30 or the its upper surface with parts carried thereby during the initial movement of arm 23 and its'pawl 26. Of course it is essential that the parts of each of the machines used for coding and decoding identically constructed and arranged, i. e., the machine used by the person decoding or decihpering the message must have its parts constructed and arranged in the identical manner as the machine used by the person coding the message. When such machines are so constructed and arranged and the several indicating marks are properly registered, successive actuation ofthe operating lever will effect identical movements of the lettered discs, and, hence, identical movements of the text elements. 7

It will thus be seen that I have provided a cryptographicmachine by means of which an exceedingly great number of messages or the like may be coded and decoded without repetition of any particular code setting, thus insuring the secrecy of such messages and rendering it practically impossible to decode the message without the possession of a similarly constructed and arranged machine and without a prior knowledge of the setting of the machine at the time the message was coded. I have also provide a novel and efficient means for successively and progressively varying the extent of movement of a movable set or sets of text elements with respect to a fixed set of text elements wherebyan exceedingly great number of relationships may be obtained between the fixed and movable sets of elements of the clear and code or cipher text. 1

It is to be understood that the forms of my invention shown and described herein are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangements of parts may be resorted to without departing from the spirit of my invention or from the scope-of the subjoined claims. The various mechanisms entering into the construction of my machine are susceptible of considerable variation and while the several forms of my invention shown and described herein constitute the preferred forms, it will be readily apparent that one skilled in the art may effect a considerable varia- 1. A cryptographic machine including a casing having a cover provided with an opening, a series of stationary spaced tabs extending. into said opening, each of said tabs having a letter on its upper surface, a first member below said cover having a first and a second series of letters on alternate letters of said first series visible between said tabs, a second member above said first member and having a series of spaced tabs each having a letter on its upper surface with the tabs of said second member overlying alternate letters of the second series on said first member, and means for moving said first and second members with respect to each other and with respect to the stationary tabs.

2. A cryptographic machine including a casing having a cover provided with a semi-circular opening, a series of spaced tabs on said cover and extending into said opening, having a' letter on its upper surface, a first disc below said cover having two series of concentrically arranged letters on its upper surface with the messages be each of said tabs alternate letters of the outermost of said series visible between said tabs, a second disc above said first disc and having a series of spaced tabs each having a letter on its upper surface with the tabs on said second disc overlying alternate letters of the innermost series of letters on said first disc, and means for rotating said first and second discs with respect to each other and with respect to the tabs on said cover.

3. A cryptographic machine including a casing having a cover provided with an opening, a series of stationary, spaced tabs extending into said opening, each of said tabs having a letter on its upper surface, a first member below said cover having a first and a second series of letters on its upper surface with alternate letters of said first series visible between said tabs, a second member above said first member and having a series of spaced tabs each having a letter on its upper surface With the tabs of said second member overlying alternate letters of the second series on said first member, means for moving said first member with respect to the stationary tabs to vary the relationshi between the letters on said tabs and the letters of said first series on said first member, and means for moving said second member with respect to the first member and to the stationary tabs to vary the relationships between the letters on the tabs on said second member and the letters of the first and second series on said first member, and between the stationary tabs and the tabs on said second member.

4. A cryptographic machine including a casing having a, cover provided with a semi-circular opening, a series of spaced tabs on said cover and extending into said opening, each of said tabs having a letter on its upper surface, a first disc below said cover having two series of concentrically arranged letters on its upper surface with alternate letters of the outermost of said series Visible between said tabs, a second disc above said first disc and having a series of spaced tabs each having a letter on its upper surface with the tabs on said second disc overlying alternate letters of the innermost series of letters on said first disc, means for rotating said first disc with respect to the tabs on said cover to vary the relationship between the letters on said tabs and the letters of the outermost series on said first disc, and means for rotating said second disc with respect to the first disc and to the tabs on said cover to var the relationships between the letters on the tabs on said second disc and the letters of the innermost and outermost series of letters on said first disc, and between the tabs on said cover and the tabs on said second disc.

5. A cryptographic machineincluding a casing having a cover provided with an opening, a series of stationary, spaced tabs extendin into said opening, each of said tabs having a letter on its upper surface, a first member below said cover having a first and a second series of letters on its upper surface with alternate letters of said first series visible between said tabs, a second member above said first member and having a series of spaced tabs each having a letter on its upper surface with the tabs of said second member overlying alternate letters of the second series on said first member, means for imparting to said first member progressive, step-by-step movements of varying extent with respect to the stationary tabs to vary the relationship between the letters on said tabs and the letters of said first series on said first member, and mean for imparting to said second member progressive step-by-step movements with respect to the first member and to the stationary tabs to vary the relationships between the letters on the tabs on said second member and the letters of the first and second series on said first member, and between the stationary tabs and the tabs on said second member,

6. A cryptographic machine including a. casing having a cover provided with a semi-circular opening, a series of spaced tabs on said cover and extending into said opening, each of said tabs having a letter on its upper surface, a first disc below said cover having two series of concentrically arranged letters on its upper surface with alternate letters of the outermost of said series visible between said tabs, a second disc above said first disc and having a, series of spaced tabs each having a letter on its upper surface with the tabs on said second disc overlying alternate letters of the innermost series of letters on said first disc, means for rotating said first disc with respect to the series of spaced tabs on said cover by progressive, step-by-step rotary increments of successively varying extent to vary the relationship between the letters on said tabs and the letters of the outermost series on said first disc, and means for rotating said second disc with respect to the first disc and to the tabs on said cover by progressive, step-by-step rotary increments to vary the relationships between the letters on the tabs on said second disc and the letters of the two concentrically arranged series of letters on said first discs, and between the tabs on said cover and the tabs on said second disc.

'7. A cryptographic machine comprising a series of spaced, stationary tabs each having a letter on the upper surface thereof, a first disc mounted for rotation below said tabs and having on its upper surface an inner and an outer series of letters with alternate letters of said outer series visible between said tabs, a first ratchet for rotating saidfirst disc, a second disc mounted for rotation above said first disc and having a. series of tabs each having a letter on its upper surface with alternate letters of said inner series of letters on said first disc visible between said tabs, a second ratchet for rotating said second disc, means for imparting to said first ratchet progressive, step-by-step movements of varying extent to vary the relationship between the letters on the stationary tabs and the letters of the outermost series of letters on said first disc, and means for imparting to said second ratchet progressive, ,step-by-step movements to vary the relationships between the letters on the tabs on said second disc and the letters of the series of letters on said first disc, and between the stationary tabs an the tabs on said second disc.

8. A cryptographic machine comprising an arcuate series of spaced, stationary tabs each having a letter on the upper surface thereof, a first disc mounted for rotation below said tabs and having on its upper surface an inner and an outer concentric series of letters with alternate letters of said outer series visible between said tabs, a first ratchet for rotating said first disc, a second disc mounted for rotation above said first disc and having a series of tabs each having a letter on its upper surface with alternate letters of said inner series of letters on said first disc visible between said tabs, at second ratchet for rotating said second disc, an operating lever for imparting to said first ratchet progressive, stepby-step movements of varying extent, and an operating lever for imparting to said second ratchet progressive, step-by-step movements.

9. A cryptographic machine comprising an arcuate series of spaced, stationary tabs each having a letter on the upper surface thereoL a first disc mounted for rotation below said tabs and having on its upper surface an inner'and an outer concentric series of letters with alternate letters of said outer series visible between said tabs, a first ratchet for rotating said first disc, a second disc mounted for rotation above said firstdisc and having a series of tabs each having a letter on its upper surface with alter-' nate letters of said inner series of letters on said first disc visible between ratchet for rotating said'second disc, a first operating lever having a pawl thereon engaging the first ratchet, means for actuating said first lever to impart thereto and to the ratchet driven therebyprogressive step-by-step movements ofvarying extent to'progressively, but to a varying degree, change the relationship between the letters of the inner and outerconcentric series of letters and said tabs, a second operating lever having a pawl thereon engaging the second ratchet, and means for actuating said second lever to impart thereto and to the ratchet driven thereby progressive step-by-step movements to progressively vary the relationships between the letters on the tabs on said second disc and the letters of the concentric series of letters on said first disc, and between the stationary tabs and the tabs on said'second disc.

10, A cryptographic member comprising an arcuate. series of spaced, stationary tabs each having' a letter on the upper surface thereof, a first disc mounted for rotation below said tabs and having on its upper surface an inner and an outer concentric series of letters with alternate letters of said outer series visible between said tabs, a first ratchet for rotating said first disc, a second disc mounted for rotation'above said first disc and having a series of tabs each having a letter on its upper'surface with alternate letters of said inner series of letters on said first disc visible between said tabs, a second ratchet for rotating said second disc, a first operating lever having apawl thereon engaging the first ratchet, means for actuating said first lever to impart thereto and to the ratchet driven thereby progressive step-by-step movements of varying extent to progressively, but to a varying degree, change the relationship between the letters of the inner and outer concentric series of letters and said tabs, a second operating lever having a pawl thereon engaging the second ratchet, and means for actuating said second lever to impart theretoand to the ratchet driven thereby progressive step-bystep movements to progressively vary the relationships between the letters on the tabs on said second disc and the letters of the concentric series of letters on said first disc, and between the stationary tabs and the tabs on said second disc,

actuation of said first operating lever effecting actuation of said second operating lever upon actuation of saidmachine.

11. A cryptographic machine comprising a first said tabs, a second member having indicia thereon constituting a first series of letters, a second member having indicia thereon constituting a second series of letters disposed adjacent said first series and movable, with respect to at least some of the letters of said first series, a lever for moving said second member and its series of letters, means for limitingthe movement of said lever in a direction to efiect movement of said second member and its'series of' letters, and means for progressively varying the extent oi movenrient of .saidilever a reverse-direction after movement of said sec ond member and its series of lettersby said lever to determine the extent of movement of said lever the extent of movement imparted to said second,

member and its series or letters by said lever as it moves in said first mentioned direction is progressively varied upon successive actuations of said lever;

' 12.v A cryptographic machine comprising a first member having indicia thereon constituting a first circular series of letters, a second member having indicia thereon constituting a second circular series of letters concentrically arranged with respect to said first series and adjacent thereto and including letters which are movable with respect to at least some of the letters of said first series, an oscillating lever for moving said second member and its series of letters, means forlimiting the movement of said lever in a direction to effect rotation of said second member and its series of letters, and means for progressively varying the extent of movement of said lever in a reverse direction after movement of said second member and its series of letters by said lever to determine the extent of movement of said lever in said first mentioned direction until such movement is arrested by said limiting means, whereby the extent of movement imparted to said second member and its series of letters by said lever as it moves in said first mentioned is progressively varied upon successive actuations of said lever.

13. A cryptographic machine comprising a first member having indicia thereon constituting a first circular series of letters, a second member having indicia thereon constituting a second cir cular series of letters concentrically arranged with respect to said first series and adjacent thereto and with respect to at least some of the letters of said first series, a ratchet for operating said second member and its series of letters, an oscillating lever having a pawl thereon for engaging said ratchet to move said ratchet and said second member and its series of letters during movement of said lever in one direction, means for limiting the movement of said lever in said one direction,

and means for progressively varying the extent of movement of said lever and pawl in a reverse direction after movement of said second member and its series of letters by actuation of said lever in said'one direction to determine the extent of movement imparted to said ratchet by said pawl and lever upon successive actuations of said lever visible between said tabs, a secondmember above said first member and having a series of spaced tabs each having a letteron its upp r surface with the tabs of said second member overlying alternate letters of the second series on said first member, a first lever for moving said first member with respect to the stationary tabs, a second lever for moving said second membe with respect to the first member and with respect to the stadirection 7 includingletters which are movable tionary tabs, and a common operating lever for actuating said first and second levers.

15. A cryptographic machine comprising a first member having indicia thereon constituting a first series of letters, a second member having indicia thereon constituting a second series of letters disposed adjacent. said first series and. movable with respect to at least some of the letters of said first series, a lever for moving said second member and its series of letters, means for limiting the movement of said lever in a direction to effect movement of said second member and its series of letters, a plurality of variously-positioned stop surfaces each adapted. to be positioned in the path of movement of said lever for contact by said lever during reverse movement thereof after said lever has been moved in said first men-. tioned direction. and such movement has been arrested by said limiting means, and means for successively presenting said stop surfaces in the path of the lever during said reverse movement for contact by said lever to successively and progressively vary the extent of movement of said lever in said reverse direction and. to consequently vary the extent of movement of said. lever during the next actuation. thereof in saidfirst mentioned direction.

16. A cryptographic machine comprising a first member having indicia. thereon constituting. a first series of letters, a second member having indicia thereon constituting a second series of letters disposed adjacent said first series andmovable with respect to at least some of they letters of said first series, an oscillating lever for moving said second member and its series ofletters, means for limiting the movement ofsaid lever in a direction to efiect movement of said second member and its series of letters, anarm carried by said lever and movable therewith, discs rotatably mounted adjacent said lever and each having thereon a plurality of variously-positioned stop surfaces each adapted to be positioned in' the athof movement. of said arm forc'ontact by'said arm during reverse movement thereof after said lever has been moved in said first-mentioned direction and such movement has been arrested by said limiting means, and means for imparting't'o said discs a progressive; step-by-step rotation durins the movement of said lever in said first mentioned direction to successively present said stop surfaces in the path of the arm during said reverse movement for contactby said] arm to suecessively and progressively vary the extent of movement ofsaid lever during'the next actuation thereof in said first mentioned direction.

17. A cryptographic machine comprising a first member having indicia thereon constituting a first series of letters, a second member'having indicia thereon constituting a second serieslotletters disposed adjacent said first. series and movable with respect to at least. some of the letters of said first series, an oscillating lever forhmov ing said secondmember ancliitsseries of? letters, means for limitin the' movement of said lever in a-direction to effect movement. of. said second member and: its series of letters, an'a'rm carried by said lever and movable therewith,- a shaft adjaoent saidlever andarm; separate discs rotatably mounted on said: shaft and each havingthereon a plurality of variously-positioned-stopsurfaces each: adapted to be positioned in the. path of movement ofsaidzarm for contact. by. saidarm during its reverse movement after the lever has been moved in said first mentioneddirection and such movement has. been arrested by said limit;

ing means, means for rotating said discs on said shaft to successively present the stop surfaces on said discs in the path of the arm during said reverse movement for contact by' said arm to successively and progressively vary the extent of movement of said lever during its next actuation in said first mentioned direction, and means for oscillating said lever.

18.. A cryptographic machine as claimed in claim 17, in which the separate discs are rotated on the shaft by rotary increments of different extents to thereby effect differential rotation of said. discs and to relatively vary the successive positions of the stop surfaces thereon for contact by the arm on the lever.

19. A cryptographic machine as claimed in claim 17 in which some of the discs are keyed together for simultaneous rotation on said shaft by rotary increments imparted thereto, and in which at least one of the other of said discs is rotated on said shaft by rotary increments of an extent different from the rotary increments imparted to said first mentioned discs.

20. Acryptographic machine comprising a first member having indicia thereon constituting a first series of letters, a second member having indicia thereon constituting a second series of letters disposed adjacent said first series and movable with respect to at least some of the letters of said first series, an oscillating lever for moving said second member and its series of letters, means for limiting the movement of said lever in a direction to effect movement of. said second member and its seriesof letters, an arm carried by said lever and movable therewith, a shaft adjacent said lever and arm, separate discs rotatably mounted on said shaft, a first. ratchet rotatably mounted on said shaft having a predetermined number of teeth and connected to at least one of the discs on said shaft. a second ratchet rotatably mounted on said shaft having a number of teeth different from the number of teeth on said first ratchet and connected to the remainder of discs on said shaft; each of said discs having thereon a plurality of variously-positioned stop surfaces each. adapted to be positioned in the path of movement of said arm fOr contact by said arm during its reverse movement after the lever has been moved in said first mentioned direction and such movement has been arrested by saidlimit ing means, means for imparting progressive step-bystep rotation to said ratchets and to thediscs connected thereto to successively present the stop surfaces on said discs in the path of the arm during such reverse movement for contact by said arm to successively and progressively vary the extent of movement of said lever'during its next actuation in said first mentioned direction, and means for oscillating saidlever.

21. A cryptographic machine comprising a first member having indicia thereon constituting. a first series of letters, a second member havingindicia thereon constituting a second. seriesof letters disposed adjacent said first series and movable with respect to at least some of the letters of said first series, an oscillating lever for moving said second member and its series of letters, an arm carried by said lever and movable therewith, a shaft adjacent said' lever and arm, a first disc mountedonsaidshaft, a second'disc mounted on said shaft adjacent saidfirst'disdsaid discs having. a plurality of variously-positioned stop surfaces adapted to be positioned in the path of movement of said arm for contact by said arm when the lever is moved. in one direction means for rotating said discs on said shaft by rotary increments of different extents to thereby effect differential rotation of said discs on said shaft to successively vary the successive positions of the stop surfaces on said discs for contact by the arm on the lever when said lever and arm are moved in said one direction, contact between said arm and said stop surfaces determining the extent of movement of said lever in an opposite direction to thereby successively vary the extent of movement of said second member and its series of letters with respect to said first member and its series of letters, and means for oscillating said lever.

22. A cryptographic machine as claimed in claim 7 in which means are provided for varying the relative position between the first disc and its associated ratchet.

23. A cryptographic machine as claimed 'in claim 20 in which means are provided for varying the relative positions of the discs with respectto 10 their associated ratchets.

BEUE TANN. 

